death, as was done by Sperry and Landé, were representative of pre-death levels. Next, Mathur’s group studied 200 individuals who had died in accidents but were free of any preceding disease. No connection was found
between cholesterol random selection. In
values and the degree of other studies that also were
These studies involved
random, similar results were reported .
The Framingham cholesterol levels of this magnitude
investigators also looked at this question.
They found a very weak correlation between
and atherosclerosis at autopsy. The correlation coefficient was generally accompany scatter plots where one can barely detect
0.36. Correlation coefficients anything other than a random
array of to small
points. In fact, those trained in the physical sciences correlation coefficients in other branches of science.
are generally appalled by Also, in the Framingham
the significance attached cohort at that time, there
were 914 deceased individuals, but the Framingham investigators selected only 127 (14%) studying atherosclerosis and cholesterol. Thus apparently this was not a random selection not describe the selection criteria. Did only 14% of the families involved allow an autopsy?
for the purpose of and the report did Two studies from
Japan claimed a Framingham study,
positive correlation, but correlation coefficients and in one study, the correlation appeared only in
were even smaller than found in the individuals with low or normal cholesterol
levels, and in
other only in the elderly. Also, for the same whether they were young or
those old. In
with very high cholesterol, the a study from Norway, claimed to
degree of support the
Cholesterol Hypothesis, many people with normal whom all three coronary vessels were constricted, those with just one constricted artery .
coronary arteries had cholesterol levels as and those with two constricted vessels had
high as those for lower levels than
Thus the autopsy studies either do not support at all the connection between circulating cholesterol and the degree of atherosclerosis, or they produce such inconsistent results or very weak correlations as to cast serious doubt on the validity of the hypothesis. And after all, these studies go rather directly to the heart of the matter (no pun intended) by looking at actual atherosclerosis in dissected coronary and other arteries.
CALCIUM SCORES The use of electron-beam tomography of coronary artery calcium (EBT CAC screening) has become a popular method for determining the extent of plaque formation and thus the degree of coronary atherosclerosis. There is even a popular book for the layman with the catchy title Track Your Plaque which has no doubt motivated many people to go out and get a so-called calcium scan. The results of the scan are generally expressed as a calcium score (CAC score), invented by Arthur Agatston M.D., a cardiologist better know to the general public as the author of the best selling book The South Beach Diet. As might be expected, there have been studies directly or indirectly addressing the simple question, is there a correlation between the calcium score and cholesterol levels. After all, if high cholesterol levels cause atherosclerosis (and strongly motivate treatment to lower them), then one might expect to see higher calcium scores associated with high levels of circulating cholesterol. The following studies address this issue:
In a study reported in 2003, 5635 men and women aged 30-76 had CAC score determinations and were followed for an average of 37 months. The positive association between the adverse CHD event frequency and CAC score was not modified by the presence or absence of elevated cholesterol, suggesting no correlation between cholesterol levels and the CAC score and thus the degree of atherosclerosis .
In a study of 6086 men and women of mean age 56-58, for men the CAC score was independent of LDL or TC. For women, only a very minimal CAC score was observed for LDL > 160 mg/dL and TC ≥
For both of these categories, the mean calcium score was 1.0, i.e. negligible . CAC scores in general range from 0 to over 400.
In the Rotterdam Coronary Calcification Study, which involved 2013 men and women age ≥ 55, after exclusion of subjects on lipid lowering drugs, no association between TC and CAC score was found for men but one was found for women . Nevertheless, women had a mean CAC score that was 1/6 those of men and was quite low.
A study reported in 2005 compared Japanese and American men, aged 40-49 by determining the CAC score and parameters which included TC and LDL. While TC and LDL were higher in the Japanese cohort, only 13% of the Japanese men but 47% of American men had CAC scores > 0. In addition, when men from the two countries with CAC score > 0 were compared, there were no significant differences in either TC or LDL .
International Health News